Composite door



F. AlJoHNsoN May 12, 1936.

COMPOS ITE DOOR Filed Oct. 11, 1935 2 Sheets-Sheet 2 Patented May 12,'y 1936 4PA'llzN'r OFFICE 2,040,259 COMPOSITE DOOR 'Fred'.a. Johnson, chicago, nl., assigner to Fred A. Johnson, Jr., Chicago, Ill.

Application October 11., 1935, Serial No. 44,509 12 claims. (ci. 20-35) The present invention relates to composite doors, and is particularly concerned with the construction of doors-preferably fabricated out of small pieces of lumber. n One of the objects of the invention is the provision of an improved door construction by means of which the door may be made lighter and practically as strong as a solid door of the same size with the use of less lumber. Another object of the invention is the provision of al1-improved door construction by means of which doors may be constructed of relatively short and thin pieces of lumber,l sometimes called lathe lumber in the trade. 1

Another object of the invention is the provision 0f animproved door construction by means of which relatively small pieces of second growth lumber not otherwise usable may be employed to construct finished doors and by means of which doors of relatively clear and perfect lumber may be constructed very economically.

In grading lumber the factors of length and width are very important, and it is more difficult to secure large pieces of lumber which are relatively clear and free of defects than it isto secure short, thin or narrow pieces of clear, perfect lumber. A door construction such as that described herein may use relatively short, narrow and thin pieces of lumber, and because of the small size of these lumber pieces practically clear and perfect lumber may be securedat a very low cost.

Another object is the provision of an improved door construction by means of which the costof a composite lumber door may be greatly reduced so as to bring the doors within the reach of a large number of purchasers who otherwise might not be able to afford such composite doors.

Other objects and advantages of the invention wiilvbe apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the two sheets of drawings, Fig. l is a front elevational view of a door ,con' 46 structed accordingto the present invention, with the door covering partially broken away to showI the details of construction V Fig. 2 is a fragmentary view of one corner of the door, with certain layers of the door broken 50 away to show the details of construction;

Fig.- 3 is Aa horizontal sectional view taken on the plane of the line 3-3 of Fig. l, looking in the direction of the arrows, showing the construction` adjacent the lock and at other parts of the door. Fig. 4 is a fragmentary view in perspective of particularly the lower left hand corner of the l' door of Fig. 6.

Referring to Figs.1 to 3, I0 indicates in its entirety the'composite door, which lxis of the flush type, as distinguished from the panel type; that is, the door is covered over-all upon bothrsides,n front and back, with a layer of finishing lumber, such as three-ply plywood II, I2 of any desired kind. The construction of the frame of the door is such that all of the other parts are fitted together to form a flush outer surface I3 on each side of the door frame, against which the plywood coverings maybe secured by gluing or any' other suitable mode of securement.

The top and bottom of the door are faced with the top strip I4 and bottom strip I5 of suitable finishing lumber, and the two edges are faced with the finishing strips I6 and I'I of suitable finishing lumber. Thus the entire outer surface of the door is covered with any desired form of finishing lumber, which may be glued to the underlying framework. i

The main part of the framework of the door comprises a. multiplicity of wooden members, indicated in their entireties by the numerals I826, which are substantially of the same shape as an I beam, the shape being modified so as to permit an approximate I beam construction out of rectangular pieces of lumber. Eachof the I beam frame members I 8--26 comprises a web member 2l and a pair of flange members 28-29.. Each flange member is mortised orprovided with a longitudinally extending groove 3D located in its inner surface midway between its edges, the groove extending into half the' thickness of the strip and being of sufficient width to receive the edge of the web 21. The web 21 and the flanges 28-29 are closely fitted and firmly glued together.

The major portion of the frame is constructed of frame members I826, and the number of such frame members employed will depend upon the width of the door. These I beam frame mem- UJI finishing strips I4 and I5.

bersV of wood are provided with relatively flat edges 3I-34 on'the flanges 28, 29 vso that when the I beams are placed side by side the edge surfaces 3I-34 may be firmly glued to the edge surfaces of adjacent wooden I beam members, as shown in Fig. 3.

In order to provide a solid lumber portion to permit the mortising in of the lock, I prefer to provide one or both edges of the door with a vertically extending rail of greater width immediately adjacent the edge finishing stripsV I6 and I1. In some embodiments of the invention, both edges of the door may be provided with such a rail and lling blocks 36, 31 extendingfto the middle portion of the door in such manner that the lock might be mortised in at either edge, but in other embodiments of the invention only one edge of the door may be made solid adjacent the lock and the door suitably marked so that the lock can be properly placed. y

The provision of a solid construction at both.

edges of the door makes the door practically fool-proof from pointof v iew of the installation of the lock, since the lock can be installed on either edge, and the carpenter cannot go wrong in his selection of the pbint of installation of the lock.

The rail 35 is of the same thickness as the finishing strips I6 and I1 from one side of the door tothe other, and it is provided with a longitudinally extending rib 38, which is of suflicient size to fill the space between the flanges 28 and 29 on ne side of the web 21 of the I beam I8. The space between the webs of I beams I8 and I9 is -lled adjacent the lock by the block 36, and the space between the webs of I beams I9 and 20 is filled by filler block 31.

In the construction of Figs. 1 to 3, the finishing strips I6 and I1 are longer than the rail 35 by the amount of the thickness of the two end The I beams `Ill- 26 are of the same length as the rail 35, so that the ends of all parts of the I beams I8-26 and rail 35 are flush with each other but spaced inward from ythe edges of the finishing pieces` II, I2, I6, I1

sufficiently to form a recess for the end pieces I4 and I5.

In addition to the'use of filler blocks 36, 31 adjacent the lock, such ller blocks may also be interposed at any other point in the framework of the door for the purpose of securing together I beams of shorter length than the complete length of the door'. The I beams are not necessarily of full length of the door, but the pieces of lumber which compose them..may be relatively short as well as thin and narrow, by the use of filler blocks which over-lap the joints of the short I beams, and are'used with glue to secure the I than the lumber itself.

beams together.

It should be understood that all of the adjacent wooden surfaces of every part inside the door are glued together, and it is a fact that when such lumber parts are `glued .together with modern methods of gluing, the joint is generally stronger The result is a composite door construction in which there are hollow spaces 39 between the wooden I beams and in which relatively short, clear and practically perfect pieces of lumber may be employed.

Referring to Figs. 4 and 5, these views show fragments of a modification embodying an improved construction atV the upper and lower edges of the door. Sincethe top and bottom of the door are substantially the same, only one end of the door need be shown. In this embodiment,

the lower finishing strip 40 is provided with a plurality of transverse grooves 4I vof substantially rectangular cross section and of sufficient size to receive the webs of wooden I beams I8-26. The web 21 of each I beam is extended beyond the flanges 28, 29 by an amount which is equal to the depth of the groove 4 I. Thus, when the ends of the flanges abut against` the fiat surface 42 of the bottom finishing strip, the web f'lts in and abuts against the bottom of the groove 4I, and all of these parts arev glued together.

In some embodiments of the invention the groove might be made to extend only across the middle portion of the strip 40 so as to receive the web without leaving a hollow space at the point 43 at each end of the groove, or the flanges may be provided With downwardly extending lugs which also extend into groove 4I. However, the most economical mode of construction is merely to leave the ends of the grooves 4I vacant adjacent the ends of the flanges 28, 29, as shown at the right 43, in Fig. 4, the elements of the'door being in close contact and glued together at all other points.

It will be evident that such a construction is more economical because it is easier and cheaper to cut the groove all the -way across the bottom finishing strip 40 and to provide the flanges 28, 29 with flat ends than it would be to fit these parts at the point 43.

In the embodiment of Figs. 6 and 7 the bottom finishing strip 44, as well as the top finishing strip, is of a modified construction, and the flanges 45 of the I beams are made shorter. In this embodiment the lower finishing .strip 44 has an upwardly extending rib 46 upon each side of which the flanges 48, 49 fit. 'I'he web 4 5 is shorter than the flanges 48, 49 by an amount equal to the height of the rib 46, so that the end surface of the web 46 engages the top of the rib 46. At each end of the nishing strip 44 there is a fiat top surface 50 for engaging the ends of the edge strip I6 and rail 35. According to this construction, there is also left one small hollow recess 5 I, which is formed by the ends of the grooves 30 in the flanges 48, 49. However, all other parts of the door frame are accurately fitted to engage each other.

The lumber of which the I beams are made need not necessarily be full door length, and in' fact may be only relatively short pieces, filler blocks being used to over-lap the joints wherever a short piece of lumber necessitates the formation of a joint. It is also preferable to stagger thejoints of the flanges and webs of any I beam member in case of the use of short strips of lumber for forming the I beam member.

y It will thus be observed that I have invented an improved flush type door in which the framework may be constructed of relatively short, narrow and thin pieces of lumber, which are otherwise not suitable for use. T he present door is approximately fifty per cent lighter than solid doors, and is practically as strong as a solid door. It. may be constructed of second growth lumber not otherwise usable, or of relatively small pieces claim is new and desire` to secure by Letters latsire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I ent of the United States, is:

1. A composite door comprising a plurality of.

pieces of finishing lumber for covering outside surfaces of a door frame, and a frame comprising a multiplicity of substantially I beam shaped members having fiat surfaces for engaging the external nishing lumber and for engaging each other, said fiat surfaces being glued together.

2. A composite door comprising a plurality of pieces of finishing lumber for covering outside surfaces of a door frame, and a frame comprising a multiplicity of substantially I beam shaped members having iiat surfaces for engaging the external finishing lumber and for engaging each other, said fiat surfaces being glued together, said I beam members each comprising a pair of end t flanges joined together by a separate web piece glued to said end flanges.

3. A composite door comprising a plurality of pieces of finishing lumber for covering outsidesurfaces of a door frame, and a frame comprising a multiplicity of substantially I beam shaped members having flat surfaces for engaging the external finishing lumber and for 'engaging each other, said fiat surfaces being glued together, said I beam members each comprising a pair of enclv flanges joined together by a separate web piece glued to said end anges,and said end flanges being grooved to receive said web. g

4. A composite door comprising a plurality of pieces of finishing lumber for covering outside surfaces of a door frame, and a frame comprising a multiplicity of substantially I beam shaped members having flat surfaces for engaging the external finishing lumber and for engaging each other, said at surfaces being glued together, and4 said door frame havingl a longitudinally extending rail of solid lumber at one edge for the purpose of. providing a suitable solid lumber portio'n of `the door for mortising .in a lock. i

5. A composite door comprising a plurality o pieces of finishing lumber for covering outside surfaces of a door frame, and a frame comprising a multiplicity of substantially I beam shaped members having -flat surfaces for engaging the' external finishing lumber and for engaging each other, said flat surfaces being glued together, said finishing pieces comprising an end nishing strip 'grooved for the reception of the web oi' said I beam members.

6.' `A composite door comprising' a plurality vof pieces of nishing lumber for covering outside surfaces of a door frame, and a frame comprising a multiplicity of substantially I beam shaped members having flat surfaces for engaging the external finishing lumber and for engaging each other, said nat surfaces being glued together, said finishing pieces comprising an end nishing strip grooved for the reception of the web of said I beam members, said I beam members hav- Y ing the web extended beyond the end anges of ing a multiplicity of substantially I beam shaped members having fiat surfaces for engginl the external lumber and for engaging each other, said ilat surfaces being glued together,

"said finishing pieces including an end strip formed with a projecting rib of rectangular cross section.

8. 'A composite door comprising a plurality of pieces of finishing lumber for .covering outside surfaces of a door frame, and a frame comprising a multiplicity of substantially I beam shaped members having fiat surfaces for engaging the external finishing lumber and for engaging each other, said flat surfaces being glued together,

frame, all of said members being glued-together to form a substantially rectangular door frame. 10. A door frame comprising a multiplicity of f longitudinally extending web `members spaced from each other, a plurality of flange members, two flange members being secured to the edges of each web member, and the `flange members being secured edge to edge to form a closed frame, all of said members being glued together to form a substantially rectangular door frame, and a multiplicity of blocks locatedv between said web members and between the flange 4members to close the spaces between said members, said blocks being glued to said flanges and webs and being located at the ends of said door frame.

` 11. A door frame comprising a multiplicity of longitudinally extending web members spaced from each other, a plurality of iiange members, two flange members being secured to the edges of each web member, and the flange members being secured edge to edge. to form a closed frame, all of said members being glued together to form a substantially rectangular door frame, and a multiplicity of blocks located between said lweb members and between the iiange members plurality of longitudinally extending wooden I beam members, each one being formed ofthree slats, one of said slats formed of web and having its edges located in grooves in the other two slats, said I beam members being arranged with the adjacent edges of the outer slats in contact with each other and glued together to form a hollow door frame, a layer of veneer on each side of said hollow door frame, and an external framework ycovering the. edges of said hollow door frame, and a plurality of blocks located at the upper andV lower edges oi' said door frame' and tting the spaces between the'webs and outer slats oi. said I beam members, the said I beams being glued togetherV at the contacting surfaces of said I beams.

, FRED A. JOHNSON. 

